Motor vehicles often include an inflatable restraint apparatus having a deployable airbag positioned in or behind an interior vehicle panel, such as an instrument panel, door panel, and the like. Many interior panels include an integrated deployment door formed into the interior panel that is designed to break free upon deployment of the airbag. Controlling the opening of the deployment door is desirable for providing a clean deployment, e.g., minimal or no fragmentation, of the airbag through the interior panel. Often an area of the interior panel surrounding the deployment door is scored or pre-weakened, e.g., via laser scoring, mechanical scoring, or the like, to form a seam that facilitates a clean airbag deployment. Additionally, supporting structures behind the interior panel can be attached to the deployment door to further control the opening of the deployment door.
In one example disclosed in U.S. Pat. No. 7,484,752, issued to Yasuda et al., an instrument panel is molded from a relatively hard and high melting point polypropylene (PP) material. A fragile splitting contour is formed into a rectangular shape along the backside of the instrument panel to define a door section that opens during airbag deployment. An airbag apparatus containing an airbag is mounted to reinforcing members and an airbag supporting frame. The reinforcing members and the airbag supporting frame are made from a relatively soft and low melting point thermoplastic material and are welded to the backside of the instrument panel along and around the door section. During airbag deployment, the airbag expands towards the door section, pushing the door section open to permit the airbag to unfold outside of the instrument panel. The soft and low melting point thermoplastic material that forms the reinforcing members and the airbag supporting frame is relatively compliant, which helps to absorb energy and control movement during airbag deployment, but the material inherently has lower mechanical properties than the hard PP material that forms the instrument panel. Moreover, it has been found that the weld strength between the soft thermoplastic material and the hard PP material is often marginal. As such, the reinforcing members and the airbag support frame can unfortunately partially or fully separate from the door section during airbag deployment, which can reduce control over the opening of the door section and result in a less clean airbag deployment.
Accordingly, it is desirable to provide interior panels having integrated airbag deployment doors for motor vehicles with improved control over the opening of the deployment door to provide a clean airbag deployment, and methods for making such interior panels. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.